Subsea Wellhead Completion Using Self-Elevating Drilling Unit
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Solution Overview
Problem
Current methods for offshore well drilling in shallow water require extensive time and cost for production platform design and installation, leaving wellheads as navigation hazards until decommissioned, and involve expensive decommissioning processes.
Innovation Solution
A self-elevating drilling unit (SEDU) method that allows wellheads to be completed at the seabed, using a novel wellhead connector and drilling spool assembly for efficient drilling and completion, enabling wells to be placed in production without surface structures and facilitating safe and cost-effective decommissioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a production platform is designed and constructed on land and moved to the well site, then the wells can be produced, but the design and construction phase takes about three years and costs several million dollars
Solution Approach 1:
The invention extracts the production equipment from the traditional surface platform configuration and relocates it to subsea level. The wellheads are completed at the seabed, and production equipment is positioned on the seafloor rather than on surface structures, eliminating the need for extensive platform design and construction while maintaining production capability.
Solution Approach 2:
The invention transitions the production system from a vertical surface-based configuration to a horizontal subsea-based configuration. By moving production equipment to the seabed dimension, the system eliminates the need for tall surface platforms and reduces the time and cost associated with platform construction while maintaining well production capability.
2Productivity
If wellheads and BOPs are located above the surface of the sea, then wells can be produced, but they constitute a hazard to navigation during production activities
Solution Approach 1:
The invention extracts the wellheads and production equipment from the surface environment and relocates them to the subsea environment. By completing wellheads at the seabed and positioning production equipment on the seafloor, the system eliminates navigation hazards while maintaining production capability.
3Object-affected harmful factors
If the decommissioning process involves cutting conductors and well production piping at the seabed, then navigation hazards are eliminated, but the process is very expensive
Solution Approach 1:
The invention performs preliminary action by completing the wellheads at the seabed during the initial drilling phase, rather than installing surface wellheads that would later require expensive decommissioning. This preliminary subsea completion eliminates the need for future decommissioning activities while maintaining production capability.
4Productivity
If a platform structure is used for production, then wells can be produced, but the platform structure must be decommissioned and removed, adding significantly to the expense
Solution Approach 1:
The invention extracts the production system from the platform structure configuration and relocates it to the subsea environment. By completing wellheads at the seabed and using subsea production equipment, the system eliminates the need for platform construction and decommissioning while maintaining production capability.
Solution Approach 2:
The invention transitions the production system from a surface platform-based configuration to a subsea-based configuration. By moving production equipment to the seabed dimension, the system eliminates the need for expensive platform structures and their associated decommissioning costs while maintaining well production capability.
Data Source
AI summary
A method and apparatus for drilling wells for producing petroleum products from an earth formation that is covered by shallow water having a depth of about 600′ or less, using a self-elevating drilling unit (SEDU) to drill one or more wells having wellheads located at or near the seabed. Well drilling is accomplished through a blowout preventer stack and a drilling spool string having a wellhead connector secured at its lower end and establishing releasable connection with the subsea wellhead. As a plurality of wells are being drilled, production of petroleum products can begin from wells that have already been completed, thus initiating an income stream from petroleum production starting only a few months from initiation of well drilling activity. When a well has been drilled, completed and rendered safe, the drilling spool string and wellhead connector is removed to the SEDU, leaving the wellhead positioned at the seabed in readiness for later production.